1. Field of Invention
The present invention relates to a serially connected axial flow fan unit.
2. Description of the Related Art
Conventionally, a cooling fan is installed inside a housing of various kinds of electronic devices to cool electronic parts thereof. As the electronic parts suffer from increased heat generation attendant with high performance and have an increased arrangement density attributable to the reduction in size of the housing, there is a need to increase the static pressure and flow rate of the cooling fan. To meet this need, a serially connected axial flow fan unit has been used as a cooling fan that can secure a large enough static pressure and an increased flow rate. The serially connected axial flow fan unit includes a plurality of axial flow fans serially connected to one another by many different methods.
In a case where the axial flow fans are coupled together by screws, rivets or the like, there is a need to form through-holes in the housings of the axial flow fans, in addition to the through-holes used in attaching the axial flow fan unit to a device. With this structure, it is difficult to re-attach the axial flow fans even though the combination of axial flow fans may be changed during the course of designing or installing the serially connected axial flow fan unit.
Once the axial flow fans are connected to one another, it is difficult to detach them without causing damage to the through-holes or the housings. Therefore, even if the combination of axial flow fans is changed during the course of designing or installing the serially connected axial flow fan unit, it is impossible to re-attach the axial flow fans without reducing the connection strength thereof.